This application claims priority to International Application No. PCT/DE00/00351 which was published in the German language on Feb. 4, 2000.
The invention relates to a transceiver unit, and in particular, to a transceiver unit for use in telecommunication systems having different transmitting/receiving frequencies.
Transceiver units are known, for example, as dual-band terminals for use in mobile radio networks operated at different frequencies. This includes terminals which can operate both in a GSM mobile radio network operated at about 900 MHz and in a mobile radio network operated at about 1800 MHzxe2x80x94usually called a PCN network. Transceiver units can also be used in mobile telecommunication terminals which operate as terminals in a mobile radio network, especially in accordance with the GSM standard, and also as a mobile station in a DECT system in single-cell arrangement, i.e. as cordless home telephone or in a multi-cell arrangement, e.g. in a corporate network.
Dual-band terminals for the 900 MHz GSM band and the 1800 MHz PCN band are known which have two power output stages with a respective adapted harmonics filter which are connected to a common antenna depending on the required operating mode of the terminal. This solution is relatively expensive and associated with a high space requirement. If only one power output stage is used, the first harmonic partially falls into the PCN receiving band in GSM transmit mode. The strong attenuation by means of a suitable harmonics filter, required in GSM operation, has a disturbing effect in PCN mode so that the (GSM) harmonics filter must be switched off in PCN mode.
The usual dual-band receivers have separate inputs for GSM and PCN signals to achieve good selectivity characteristics. For this reason, the GSM or, respectively, PCN signal component must be separated from the total antenna signal. A special filter or switching unit is used for this purpose.
Finally, since transmitter output and receiver input act in conjunction with a single antenna, a transmitter/receiver switch (TX/RX switch) is needed which either connects the power output stage at its output, or the receiver input at its input, to the antenna. A RF-rated switch is used for this purpose.
In one embodiment of the invention, there is a transceiver unit for operation at least a first and second transmitting/receiving frequency, comprising: at least one power output stage, a receiving section having a first and a second input, at which it is tuned to the first and second transmitting/receiving frequency; and a transmitting/receiving antenna used for the first and second transmitting/receiving frequency, wherein a power output stage for the first and second transmitting frequency and a switchable filter element via which the power output stage and the first and second input of the receiving section can be connected to the transmitting/receiving antenna.
In one aspect of the invention, the filter element has separate taps for connection to the output of the power output stage and the first and second input of the receiving section, wherein an RF switch is provided between the first and second input of the receiving section and the corresponding taps of the filter element.
In another aspect of the invention, the filter element comprises a plurality of RF conductors or conductor sections, the respective electrical length, conductor track width and concatenation configuration for implementing predetermined attenuation characteristics are tuned to the first and second transmitting/receiving frequency.
In still another aspect of the invention, the filter element is formed from coherent conductor sections of a conductor train.
In yet another aspect of the invention, transmitting/receiving signals are processed having a first and second transmitting/receiving frequency, the second transmitting/receiving frequency being approximately twice the first transmitting/receiving frequency.
In another aspect of the invention, the filter element comprises a first, second, third, fourth and fifth node and a first, second, third, fourth and fifth RF conductor or conductor section, the first node being located at the output of the power output stage, the first conductor section having a first electrical length and extending between the first node and the second node, the second conductor section having a second electrical length and extending between the first node and a ground connection, the third conductor section having substantially the second electrical length and extending between the second node and the third node connected to the first input of the receiving section and ground, the fourth conductor section having substantially the first electrical length and extending between the second node and the fourth node which is associated with the transmitting/receiving antenna, and the fifth conductor section having substantially the second electrical length and extending between the fourth node and the fifth node connected to the second input of the receiving section and ground.
In yet another aspect of the invention, the end at the ground connection end of the second conductor section and the fourth and fifth node are associated with an RF ground switch.
In still another aspect of the invention, the first electrical length has a value of about xcexxe2x85x9 and the second electrical length has a value of about xcexxc2xc referred to the wavelength xcex1 corresponding to the first transmitting/receiving frequency.
In one aspect of the invention, the transmission unit is a dual-band transceiver unit having a first transmitting/receiving frequency of about 900 MHz for a GSM mobile radio network and a second transmitting/receiving frequency of about 1800 MHz.
In another aspect of the invention, the RF conductors or conductor sections are constructed in stripline or microstrip technology.
In still another aspect of the invention, the RF switches are constructed as PIN diodes or GaAs FET switches.
In yet another aspect of the invention, the transceiver unit operates in a system having mobile telecommunication systems using different transmitting/receiving frequencies.
In another aspect of the invention, the filter element comprises a first, second, third, fourth and fifth node and a first, second, third, fourth and fifth RF conductor or conductor section, the first node being located at the output of the power output stage, the first conductor section having a first electrical length and extending between the first node and the second node, the second conductor section having a second electrical length and extending between the first node and a ground connection, the third conductor section having substantially the second electrical length and extending between the second node and the third node connected to the first input of the receiving section and ground, the fourth conductor section having substantially the first electrical length and extending between the second node and the fourth node which is associated with the transmitting/receiving antenna, and the fifth conductor section having substantially the second electrical length and extending between the fourth node and the fifth node connected to the second input of the receiving section and ground.
In still another aspect of the invention, the filter element comprises a first, second, third, fourth and fifth node and a first, second, third, fourth and fifth RF conductor or conductor section, the first node being located at the output of the power output stage, the first conductor section having a first electrical length and extending between the first node and the second node, the second conductor section having a second electrical length and extending between the first node and a ground connection, the third conductor section having substantially the second electrical length and extending between the second node and the third node connected to the first input of the receiving section and ground, the fourth conductor section having substantially the first electrical length and extending between the second node and the fourth node which is associated with the transmitting/receiving antenna, and the fifth conductor section having substantially the second electrical length and extending between the fourth node and the fifth node connected to the second input of the receiving section and ground.
In another aspect of the invention, the first electrical length has a value of about xcexxe2x85x9 and the second electrical length has a value of about xcexxc2xc referred to the wavelength xcex1 corresponding to the first transrnitting/receiving frequency.